Chris Oubre

Plasmon hybridization in nanoshell dimers

We extend the plasmon hybridization method to investigate the plasmon modes of metallic nanoshell dimers. The formalism is also generalized to include the effects of dielectric backgrounds. It is shown that the presence of dielectrics shifts the plasmon resonances of the individual nanoparticles to lower energies and screens their interaction in the dimer configuration. The net result is a redshift of dimer energies compared to the system without dielectrics and a weaker dependence of the dimer plasmon energies on dimer separation. We calculate the plasmon energies and optical absorption of nanoshell dimers as a function of dimer separation. The results are in excellent agreement with the results of finite difference time domain simulations.

Finite difference time-domain studies of optical properties of nanoshell structures

The optical properties of metallic nanoshell systems are investigated using the Finite Difference Time Domain (FDTD) method. The method provides a convenient approach for calculating several physical properties of nanoshells based structures including the optical absorption and scattering cross sections as well as the local electromagnetic fields near the nanoshell surfaces. The method is applied to silver and gold nanoshells and nanoshell dimers. Comparisons with classical Mie scattering are presented.

Finite difference time domain studies of the local electric field enhancements near nanoshell structures

The local electric field enhancements around various nanoshell structures are investigated using the Finite Difference Time Domain (FDTD) method. The method provides a convenient and systematic approach for calculating several physical properties of nanostructures, including the optical absorption and scattering cross sections as well as the local electromagnetic fields. The method is applied to single uniform nanoshells as well as nanoshells with surface defects and structural distortions. The results show that, while defects can significantly affect local electric field enhancements, far field results such as extinction spectra can be remarkably insensitive to defects and distortions.